1. Field of the Invention
Embodiments of the invention relate to digital triggering of signals.
2. Discussion of the Background
A digital oscilloscope can now present analog signals very accurately on a display device after sampling the analog signal over time and digitize the sampled values of the analog signal at the individual sampling times by means of analog-digital conversion.
The triggering of the digitized signals to be presented on the display device of the digital oscilloscope is now also realized in digital manner. In the document DE 39 36 932 A1, an analog signal converted into the digital data format is compared in a comparator with reference to overshooting or undershooting a threshold value stored in a register. The first overshooting or undershooting of the threshold value by one of the sampled values of the analog signal to be presented is identified by the triggering system as a triggering time and leads to a triggering impulse, which is used in the display device for recording the signals to be presented synchronously with the triggering impulse.
The digital triggering of DE 39 36 932 A1 implements only a static triggering on the basis of a single signal-level comparison with one threshold value. The fact that a dynamic triggering on the basis of a time-dependent signal feature—for example, a triggering on the basis of a signal slope of the signal, a duration of a signal impulse or a time delay of a signal impulse by comparison with a reference impulse—is not yet possible using a digital triggering system of this kind is disadvantageous.